JP6173574B2 - Method of operating an apparatus for providing a liquid additive - Google Patents

Description

  The invention relates to a method for operating a device for providing a liquid additive and to a corresponding device for carrying out the method according to the invention.

Devices for providing liquid additives are used in the automotive field, in particular for supplying liquid additives to automobile exhaust gas treatment devices. Of particular importance are exhaust gas treatment devices in which nitrogen oxide compounds in the exhaust gas of an internal combustion engine are reduced using a reducing agent, thereby forming harmless substances such as nitrogen, CO ₂ and water. The corresponding exhaust gas method is called the SCR (Selective Catalytic Reduction) method.

  Ammonia is usually used as the reducing agent for this process. Ammonia is usually stored in the form of a reducing agent precursor solution that can be stored as a liquid additive and provided to the exhaust gas treatment device as a liquid additive rather than directly. The liquid additive is then converted in the exhaust gas by heat or hydrolysis to form the actual reducing agent ammonia. “Hydrolysis” means that the conversion reaction is assisted by a hydrolysis catalyst that may be provided to the substrate honeycomb body in an exhaust gas treatment device, for example. In the case of the SCR method, an aqueous urea solution having a urea content of 32.5% is available under the trade name AdBlue®.

  The problem with such liquid additives is that they can freeze at low temperatures. The 32.5% urea aqueous solution is frozen at, for example, -11 ° C. In the automotive field, such low temperatures can occur during prolonged outages, especially in winter. To be able to operate devices that provide liquid additives even at low temperatures despite the risk of freezing, and to enable such devices to operate quickly, especially after prolonged outages It is known that the device is at least partially drained after being deactivated. This can ensure that there is no liquid additive in at least a part of the device, so that freezing cannot occur there. Furthermore, it is further known that a heater is provided for a device that provides a liquid additive, which can heat at least a portion of the device. Heating can prevent the liquid additive from freezing, or the frozen liquid additive can be thawed again.

  Despite the above measures, it is usually not possible to quickly operate the device if the liquid additive in the tank and in the delivery unit supplying the liquid additive is completely frozen. Rather, the liquid additive in the tank needs to be at least partially dissolved. The liquid additive in the delivery unit must usually be completely thawed or the delivery unit is drained prior to the freezing process. The thawing of the frozen additive takes a certain period of time. This is because a certain minimum amount of energy is required for thawing the corresponding volume of liquid additive, but this energy can only be provided at a limited rate.

  With this as a starting point, the task of the present invention is to solve or at least reduce the technical problem. Describe a particularly advantageous method of operating a special device that provides a liquid additive, especially rarely frozen and that is particularly easy to thaw when frozen additive is present in the device Is required.

  The object is achieved by a method according to the features of claim 1. Further advantageous refinements of the invention are specified in the dependent claims. The features individually recited in the claims may be combined with each other in any desired technically meaningful manner, and may be combined with the description, particularly with reference to the drawings, in which alternative embodiments of the invention are specified. May be supplemented by explanations from.

The present invention is a method of operating a device for providing a liquid additive having a delivery path extending from a tank to an additive dispensing device, wherein at least one section of the delivery path forms a jacket, comprising at least: Steps:
a) delivering the liquid additive from the tank to the additive distributor along the delivery path in the delivery direction;
b) stopping the transmission;
and c) draining a section of the delivery path, and d) forming a thermal insulation in the jacket by the drained delivery path.

  Devices that provide liquid additives typically have a delivery unit that delivers the liquid additive. For the delivery process, the delivery unit usually has a pump. The delivery unit may further have another active component. Such a component is, for example, a valve that controls the delivery of the liquid additive or a sensor that monitors the delivery of the liquid additive. In addition to delivering liquid additive, the delivery unit may meter in liquid additive. For this purpose, the delivery unit may have, for example, a pump whose delivery speed is precisely adjustable. This is possible, for example, in the case of several reciprocating pistons or diaphragm pumps where the delivery speed is proportional to the number of delivery strokes made by the pump. It is also possible that the pump does not perform a metering function, but rather simply causes a predetermined pressure increase and provides the additive distributor with liquid additive at a predetermined pressure.

  The additive distributor may be, for example, a supply device that can supply the liquid additive to the exhaust gas treatment device. The additive dispensing device may include a nozzle that can dispense the liquid additive to the exhaust gas treatment device in a final sprayed form. Furthermore, the additive dispensing device may have a metering valve that can meter the liquid additive. The metering valve is particularly advantageous when the delivery unit does not perform the metering function.

  The delivery path is the path from the tank where the liquid additive is stored to the additive dispensing device. The delivery path is usually formed by a line that may be formed, for example, by a hose. It is also possible for the delivery path to be formed by a bore in the block in at least a plurality of sections. Such a block may be, for example, an assembly base body to which the active components described above are attached.

  The jacket formed by the delivery path is, for example, a section of the delivery path that extends along a plane. The surface preferably partitions a predetermined area of the apparatus from another area of the apparatus so that the areas of the additive dispensing device are thermally separated from one another by thermal insulation in the jacket. The section of the delivery path forming the jacket may be, for example, a wound meandering form. Thereby, the individual turns of the section of the delivery path form a jacket. The delivery path can also be formed as a planar cavity in the area of the jacket. Such planar cavities have a two-dimensional extent.

  During delivery of the liquid additive in step a), the device is normally operating. An internal combustion engine of a motor vehicle having the above-described device is typically operating during step a) and generates exhaust gas in this process, which is sent to an exhaust gas treatment device. In order to purify the exhaust gas, the device supplies a liquid additive to the exhaust gas treatment device of the automobile.

  The sending of the device is stopped in step b). Step b) is usually carried out as part of stopping the operation of a motor vehicle having the device described above. In parallel with the stoppage of delivery, a routine is usually performed, which places the device in an operatively stopped state. Such a routine may be, for example, storing the amount of liquid additive provided by the device in an electronic memory. The information can later be used to update an item of information regarding the level of liquid additive filling in the tank. As part of the routine for stopping delivery, at least partial drainage of the section of the delivery path in step c) is also performed. The drainage has the effect of preventing the additive from freezing in the delivery path, especially when low temperatures are present.

  In step d), a heat insulation is formed on the jacket. This is done by replacing the liquid additive in the section with a surrogate substance in parallel with draining in step c). The formation of the thermal insulation is usually realized by a surrogate material having a thermal conductivity much lower than that of the liquid additive. The substitute material may be air, for example. The thermal conductivity of air is several times lower than that of the liquid additive. After step d), heat in the region of the section of the delivery path is transferred between the different wall sections of the delivery path substantially only by heat radiation. Heat transfer by heat conduction through the liquid additive or exchange material virtually no longer occurs. Therefore, the thermal conductivity through the jacket is greatly reduced after step d).

  The formation of the heat insulation described above makes it possible to guarantee the target freezing of the device. The outflow of heat from the device can be controlled in an effective manner by the insulation. Furthermore, the device is better insulated as necessary and can slow down the freezing process over time. In short, the number of freezes of the device can be greatly reduced thereby. In addition, the heat insulation allows for the targeted heating of the device, so that even if frozen liquid additive is present in the device, the device can be operated more quickly after the operation is stopped. Areas that do not need to be heated are insulated from areas that need to be heated. Thermal energy is not used and does not flow into areas where no thermal energy is required.

  The method is particularly advantageous if the section of the delivery path is drained by the liquid additive being fed back from the delivery path to the tank in the opposite direction to the delivery direction.

  The aforementioned drainage of the delivery path may be realized, for example, by a pump provided in the delivery unit of the device, which pump has a reversible delivery direction. The pump or delivery unit may have at least one valve for reversing the delivery direction. Pump delivery may be reversed, for example, by switching the delivery unit or pump valve such that the delivery unit delivers the liquid additive in the opposite direction of delivery. The pump delivery direction can also be changed by actuating the pump drive in different directions. This may be achieved, for example, by reversing the polarity of the pump drive. Another possibility for drainage of the delivery path is to provide not only a pump for delivery of the liquid additive but also a second pump for drainage in the device, by means of this second pump. Draining can be performed.

  The drainage of the delivery path by the liquid additive being fed back into the tank is particularly advantageous. This is because such a drainage does not cause a loss of liquid additive. The liquid additive removed from the delivery path becomes available again at the beginning of subsequent operation of the device.

  Another possibility for drainage of the delivery path is that drainage is realized by circulation. In this case, a branch path from the delivery path that normally returns from the delivery path to the tank is provided. Thereby, the liquid additive in the delivery path may be fed back to the tank by being circulated through the branch path from the delivery path. The branch path may be called a return line.

  The method is further advantageous when the section of the delivery path is drained by at least partially evaporating the liquid additive in the section of the delivery path.

  For evaporation of the liquid additive, the device may have a heater. Evaporation of the liquid additive in the delivery path section may be accomplished, for example, by the heater heating the liquid additive in the delivery path section until the liquid additive evaporates. Additives that have changed to a gaseous state usually have a significantly lower thermal conductivity than liquid additives. Thereby, a heat insulation part is also formed by evaporation of a liquid additive.

  Such an embodiment of the method is advantageous because the means for draining the delivery path is particularly simple in this case. In particular, the pump or delivery unit of the device need not have a reversible delivery direction. Only the heater described above is required in the apparatus.

  However, in the implementation of the method, the liquid additive can be chemically converted because the conversion temperature of the liquid additive is close to the evaporation temperature. The chemical transformation can be problematic because it can result in the formation of contaminants in the device. However, the advantage of a simpler configuration of the device may outweigh this problem.

  There is also a need to describe an apparatus for carrying out the described method, which has a delivery unit and the jacket at least partly surrounds the delivery unit.

  Special advantages and design features manifested with respect to the described method can be applied and transferred to the described apparatus as well. The same applies to the special advantages and design features of the device described below that can be applied and transferred to the method.

  In particular, it is particularly advantageous if the jacket is arranged between the delivery unit of the device and the interior of the tank for the liquid additive. Thereby, the heat insulation part in a jacket insulates the inside of the tank in which the liquid additive is stored with respect to the delivery unit. Thus, the arrangement of the jacket and the insulation allows the freezing behavior and thawing of the liquid additive inside the tank and the delivery unit to be influenced separately from each other. This makes it possible to prepare the delivery unit for operation particularly quickly after the operation has stopped. This is because the liquid additive in the delivery unit can be heated in a targeted manner and in particular a small amount of liquid additive in the tank can be additionally heated in a targeted manner. . Unnecessary escape of heat to areas of the tank that do not need to be thawed to start the device can be prevented. When the liquid additive has been completely removed from the delivery unit during the drainage in step c), the heat insulation prevents the heat from flowing to the delivery unit and the predetermined area of liquid additive inside the tank It is also possible to decompress only in the targeted format. Thereby, heat conduction from the heater to the delivery unit is generally not required. This is because there is no frozen liquid additive in the delivery unit due to drainage. This also facilitates a particularly quick start-up of the device after deactivation if the liquid additive has at least partially frozen.

  The apparatus has a heater, and the jacket is at least partially disposed between the heater and the delivery unit so that the insulation in the jacket at least partially insulates the delivery unit from the heater. The device is more advantageous.

  Thereby, in this embodiment, the heater is arranged on the side of the jacket where the inside of the tank is also arranged. The delivery unit is insulated from the heater. Such an arrangement is particularly advantageous if the delivery unit is completely drained during drainage in step c) and the liquid additive is completely free from the delivery path. This allows the heat energy generated by the heater to be introduced in a targeted manner into the area inside the tank where the liquid additive is present, thereby starting the operation of the device. A predetermined starting volume of liquid additive that can be made available particularly quickly.

  The heater has at least one active heating section and at least one passive heat distribution section, the passive heat distribution section being insulated from the delivery unit by an insulation in the jacket; The device is further advantageous.

  In one embodiment of the apparatus, the heat distribution section and the heating section are insulated from the delivery unit by insulation. In another design aspect, only the heat distribution section is insulated from the delivery unit by insulation. In the area of the heating section, the delivery path does not form a jacket. In this case, however, another (conventional) insulation may be formed, for example consisting of an insulation mat, in order to also insulate the heating section from the delivery unit.

  In such an arrangement, at least a portion of the thermal energy generated by the heater is also introduced into the delivery unit, so that the delivery unit can be removed from the freezing temperature along with the liquid additive, even in the case of prolonged shutdown. Is also heated quickly. This is also advantageous if the delivery unit is completely drained during drainage in step c). In this case, it is very advantageous that the molten liquid additive inside the tank is fed into the delivery unit when it is still below the freezing temperature. This is because the liquid additive may freeze rapidly in the delivery unit. This can be prevented by at least the active heating section not being insulated from the delivery unit. Furthermore, electrical contact of the active heating section is usually necessary for electrical energy to be provided to the heater. Electrical contact is usually achieved via a delivery unit. A control unit that controls the supply of heating energy to the heater is disposed in the delivery unit. Electrical contact through the insulation formed in the jacket is cumbersome. However, electrical contact can extend through conventional insulation. It is therefore advantageous if the active heating section is not separated from the delivery unit by a jacket so that an electrical line can extend from the delivery unit to the active heating section.

  The device is further advantageous if a filter for filtering the liquid additive in the delivery path is arranged in the area of the jacket.

  The delivery path usually has to have a planar extent in the area of the jacket in order that the insulation can be designed in an effective manner for structural reasons. The available space is particularly suitable for accommodating a filter for filtering liquid additives. The filter should usually have a large area so that the filter is not clogged with contaminants. Thereby, providing a filter in the area of the jacket in the delivery path has the positive synergistic effect that the section of the delivery path for the jacket is additionally used in a particularly space-saving manner.

  A delivery unit is disposed in the partitioned chamber in the tank for liquid additive, and a jacket extends at least partially along the wall of the partitioned chamber to form a planar cavity, thereby The apparatus is further advantageous if the heat insulating part insulates the partitioned chamber from the inside of the tank.

  It is particularly advantageous to provide a partitioned chamber for the delivery unit in the liquid additive tank. This is because this allows the delivery unit to be arranged in a particularly space-saving manner. In particular, no additional structural space for the delivery unit is required in the automobile. Furthermore, in such a design, the mounting area for the delivery unit must be provided only to the tank. No special configuration of the vehicle is necessary to allow the delivery unit to be installed. Furthermore, no adaptation of the delivery unit to the structural space available in the automobile is necessary. The tank forms an interface by which the delivery unit is attached together with the vehicle.

  However, if the delivery unit is located in a tank, it is usually more difficult for the delivery unit to be insulated from the liquid additive inside the tank. The disadvantages are overcome by the apparatus described herein. A particularly effective thermal insulation can be provided between the tank interior and the delivery unit in the partitioned chamber in the tank.

  A delivery path is formed in the region of the jacket by a planar cavity between the wall of the partitioned chamber and a bell-shaped cover surrounding the partitioned chamber, the delivery path being the base of the bell-shaped cover The device is further advantageous if it opens from the inside of the tank into the planar cavity in the region and exits the planar cavity through at least one internal suction point in the upper region of the bell-shaped cover.

  There is a gap between the wall of the partitioned chamber and the bell-shaped cover. The gap forms a planar cavity. The planar cavity is preferably in the form of a hollow cylinder. In the base region, the planar cavity is connected to the inside of the tank via an annular gap. The base region is preferably referred to as the base region because it is located near the tank base. The upper region is preferably referred to as the upper region because it is disposed on the bell-shaped cover on the upper side opposite the base region. The bell-shaped cover is preferably closed in the upper region by a cap or lid. The internal suction point is preferably formed by an opening or bore through which the liquid additive can be sucked out of the planar cavity into a partitioned chamber or delivery unit. Thereby, the liquid additive flows into the planar cavity in the base region through the annular gap and exits the planar cavity in the upper region through at least one suction point. Thus, the planar cavity between the partitioned chamber wall and the bell-shaped cover is part of the delivery path.

  If the planar cavity is drained in method steps c) and d), the delivery path downstream of the planar cavity as viewed in the flow direction is preferably liquid-tight and air-tight. Therefore, the follow-up flow of the liquid additive from the tank to the planar cavity can be prevented. Due to the gas pressure of the substitute medium (usually air) in the planar cavity in the form of a diving bell, no liquid additive enters the planar cavity.

  The filter for filtering the liquid additive is preferably arranged in the planar cavity. The filter is preferably arranged parallel to the wall and preferably also parallel to the area of the bell-shaped cover. Therefore, a filter with a particularly large surface area can be arranged in the planar cavity. The surface area of the filter preferably corresponds (approximately) to the total surface area of the planar cavities.

  The wall of the partitioned chamber and the bell cover are made of plastic, and at least one section of at least one heater for heating the liquid additive inside the tank is at least partially embedded in the bell cover. And the device is further advantageous.

  The bell may be manufactured as an injection molded part, for example. The heater may be formed from, for example, an electrical resistance conductor or a PTC (positive temperature coefficient) conductor that performs active heating by current flow. The heater can also be formed from an active heating section and a passive heat distribution section, with only the passive heat distribution section embedded in the bell-shaped cover. The plastic material of the bell-shaped cover protects the heater from liquid additives that usually have a high corrosive action. The bell-shaped cover may be manufactured, for example, by an injection molding method, and the heater is placed in an injection mold and thereby encapsulated by plastic. As long as the passive heat distribution section is embedded in the cover, the active heating section may be attached to the bell-shaped cover from the inside and connected to the passive heat distribution section.

  The bell-shaped cover may be fixedly connected to the chamber or the wall of the chamber. The bell-shaped cover and chamber are preferably manufactured as one injection molded component. The partitioned chamber and bell-shaped cover may be inserted into the tank base for the liquid additive so as to extend from the tank base into the tank interior of the subsequent tank. For this purpose, the tank may have an opening in the base into which the partitioned chamber is inserted. The tank may also be made from plastic. The partitioned chamber and tank may be fixedly connected to each other by a weld seam.

  The invention is also intended herein to describe an automobile having an internal combustion engine, an exhaust gas treatment device for purifying the exhaust gas of the internal combustion engine, and a device capable of supplying a liquid additive to the exhaust gas treatment device. ing.

  The described method can be carried out by means of a motor vehicle. The exhaust gas treatment apparatus for an automobile is preferably provided with an SCR catalytic converter. In this SCR catalytic converter, a selective catalytic reduction method is used to purify the exhaust gas of the internal combustion engine using the supplied liquid additive. Can be done for.

  The invention and the technical field are explained in more detail below on the basis of the drawings. Although the drawings show a particularly preferred exemplary embodiment, the invention is not limited thereto. In particular, it should be noted that the drawings, particularly the illustrated proportions, are merely exemplary.

1 shows a first design aspect of the described device. 2 shows a second design aspect of the described device. Fig. 3 shows a three-dimensional view of the described device. 1 shows one embodiment of a jacket for the described device. Fig. 2 shows a flow chart of the described method. Fig. 2 shows an automobile with the described device.

  Two embodiments of the described device 1 shown in FIGS. 1 and 2 are first described together and the differences will be discussed later. The apparatus 1 shown in FIGS. 1 and 2 each has a tank 4 in which a liquid additive 2 can be stored. A partitioned chamber 14 is disposed in the tank 4. The partitioned chamber 14 is partitioned by a wall portion 15 from the tank interior 16 in which the liquid additive 2 is stored.

  A delivery unit 10 is disposed in the partitioned chamber 14, and the liquid additive 2 can be extracted from the tank 4 by the delivery unit 10. For this purpose, a delivery path 3 is provided which extends from the tank interior 16 through the delivery unit 10 to an additive distributor (not shown here). The delivery unit 10 can supply the liquid additive 2 from the tank 4 along the delivery path 3 to the additive distributor (not shown).

  The chamber is partitioned so that the liquid additive 2 is withdrawn from the tank 4 by the delivery unit 10 near the tank base and the liquid additive 2 in the tank 4 can be withdrawn as completely as possible by the delivery unit 10. 14 is arranged on the base of the tank 4. The partitioned chamber 14 is provided with a bell-shaped cover 20 that covers the partitioned chamber 14. The bell-shaped cover 20 and the partitioned chamber 14 are formed as one component in FIGS. 1 and 2. However, the partitioned chamber 14 and bell-shaped cover 20 may be two separate components attached to each other.

  A planar cavity 17 formed by a gap 19 between the bell-shaped cover 20 and the wall portion 15 is provided between the bell-shaped cover 20 and the wall portion 15 of the partitioned chamber 14. The planar cavity 17 forms a section 6 of the delivery path 3 from the tank 4 to the delivery unit 10. A filter 18 for filtering the liquid additive 2 is disposed in the planar cavity 17. The delivery path 3 opens into the planar cavity 17 in the bell-shaped cover 20 and the base region 21 of the tank 4. The delivery path 3 exits the planar cavity 17 in the upper region 22 of the bell-shaped cover 20 at the internal suction location 23. As a result, the bell-shaped cover 20 acts in the form of a diving bell when drained, and no follow-up flow of the liquid additive 20 from the tank into the bell-shaped cover 20 occurs.

  In the state shown in FIGS. 1 and 2, the liquid additive 2 is present only in the tank interior 16 of the tank 4 and not in the delivery path 3, and thus the jacket 7, the planar cavity 17 or the section 6. Does not exist. Therefore, a heat insulating portion 9 is formed in the section 6, the jacket 7, and the planar cavity 17, and the heat insulating portion insulates the delivery unit 10 from the tank interior 16.

  The apparatus 1 shown in FIGS. 1 and 2 has a heater 11 on a bell-shaped cover 20. For example, the heater 11 may be integrally embedded in the bell-shaped cover 20 when the bell-shaped cover 20 is molded. The heater 11 has an active heating section 12 and a passive heat distribution section 13, and the heat generated in the active heating section 12 is targeted by the passive heat distribution section 13. Distributed in the form of In FIG. 1, the heat insulating portion 9 provides heat insulation of the delivery unit 10 to the tank interior 16 only on the peripheral surface of the partitioned chamber 14.

  In FIG. 2, a planar element 29 is additionally provided in the delivery path 3, and this planar element connects the partitioned chamber 14 and delivery unit 10 to the liquid additive 2 in the tank 4 and the tank interior 16. Therefore, it is possible to realize the heat insulating portion 9 also in the upper region 22 in order to realize a more complete heat insulating portion 9. 1 and 2, each of the partitioned chambers 14 is closed by a lid 31 from the outside of the tank 4 so that the delivery unit 10 is protected from contaminants or moisture from the outside. .

  FIG. 3 shows a three-dimensional view of the device 1. In FIG. 3, a partitioned chamber 14 with a delivery unit 10 arranged therein can be seen. The bell-shaped cover 20 is disposed around the outside of the partitioned chamber 14. A planar cavity 17 is provided between the bell-shaped cover 20 and the wall 15 of the partitioned chamber 14, and the planar cavity 17 constitutes one section 6 of the delivery path 3. A jacket 7 is formed around the partitioned chamber 14 and the delivery unit 10. The delivery unit 10 can deliver the liquid additive from the tank in the delivery path 8 in the delivery direction 8. The delivery path 3 opens from a tank (not shown) into the planar cavity 17 or the jacket 7 of the delivery path 3 in the base region 21, and the planar cavity 17 or jacket 7 at the internal suction point 23 in the upper region 22. Out of. When the liquid additive is not present in the jacket 7 and the planar cavity 17, the heat insulating portion 9 is formed.

  FIG. 4 shows another embodiment of one section 6 of the delivery path 3 that forms the jacket 7. Here, the delivery path 3 is formed in the form of a spiral having a plurality of winding portions 30 forming the jacket 7. As a whole, the delivery path 3 forms a planar element 29 with a helical configuration. Such an embodiment of the jacket 7 by the delivery path 3 is probably not preferred. This is because the bulkheads between the individual turns of the delivery path 3 in the jacket 7 each form a thermal bridge through the jacket 7 and at the same time flow resistance to the liquid additive through the delivery path 3 passes through the jacket 7. This is because the length of the delivery path 3 is particularly large. Nevertheless, the design aspect shown in FIG. 4 constitutes an alternative design for the jacket 7.

  FIG. 5 shows a flowchart of the described method. It can be seen how the method steps a) to d) are carried out continuously. The delivery of the liquid additive takes place in step a), the delivery is stopped in step b), the section of the delivery path is at least partially drained in step c), and the delivery in step d) as a result of drainage. A heat insulating part is formed in the jacket of the path.

  FIG. 6 shows an automobile 24 having an internal combustion engine 25 and an exhaust gas treatment device 26 for purifying exhaust gas from the internal combustion engine 25. The exhaust gas treatment device 26 is provided with an SCR catalytic converter 28, and the selective catalytic reduction method can be performed by the SCR catalytic converter 28. For the selective catalytic reduction process, the liquid additive can be supplied to the exhaust gas treatment device 26 by the additive distributor 5. The liquid additive is supplied from the tank 4 to the additive distributor 5 through the line 27 by the device 1. For this purpose, the liquid additive is delivered by the device 1 to the additive dispensing device 5 along the delivery path 3.

  The methods described herein and the apparatus described herein are particularly rapid and quick to provide an apparatus that provides a liquid additive after the liquid additive has been frozen in the apparatus during a long-term vehicle outage. It is particularly advantageous to ensure that it can be reliably prepared for operation.

DESCRIPTION OF SYMBOLS 1 apparatus 2 liquid additive 3 delivery path 4 tank 5 additive distribution apparatus 6 section 7 jacket 8 delivery direction 9 heat insulation part 10 delivery unit 11 heater 12 heating section 13 heat distribution section 14 partitioned chamber 15 wall part 16 tank interior 17 Planar cavity 18 Filter 19 Gap 20 Bell-shaped cover 21 Base region 22 Upper region 23 Internal suction location 24 Automobile 25 Internal combustion engine 26 Exhaust gas treatment device 27 Line 28 SCR catalytic converter 29 Planar element 30 Line winding part 31 Lid

Claims (10)

A delivery path (3) extending from the tank (4) to the additive distributor (5);
A chamber (14) disposed in the tank interior (16) of the tank (4) and partitioned from the tank interior (16) by a wall (15);
Disposed in the partitioned chamber (14) within the liquid additive from the tank interior (16) and (2) delivery unit extracting (10) has a,
A jacket (7) formed by at least one section (6) of the delivery path (3) at least partially surrounds the partitioned chamber (14 ) and forms a planar cavity (17). cage, thereby, the jacket (7) is characterized by forming a heat insulating portion for insulating the (9) the partitioned chamber (14) with respect to the tank interior (16), a liquid additive An apparatus for providing (2) . A heater (11), the jacket (7) being at least partly arranged between the heater (11) and the delivery unit (10), thereby insulating the jacket (7); part (9) is at least partially thermally insulating said delivery unit (10) to said heater (11), the apparatus of claim 1, wherein. The heater (11) has at least one active heating section (12) and at least one passive heat distribution section (13), the passive heat distribution section (13) 3. The device according to claim 2 , wherein the insulation unit (9) in the jacket (7) is insulated from the delivery unit (10). Device according to any one of claims 1 to 3 , wherein a filter (18) for filtering the liquid additive in the delivery path (3) is arranged in the region of the jacket (7). The delivery path (3) includes a wall (15) of the partitioned chamber (14) and a bell-shaped cover (20) surrounding the partitioned chamber (14) in the region of the jacket (7). Between the tank interior (16) and the planar cavity (16) in the base region (21) of the bell-shaped cover (20). 17) is open to, and the coming out of the planar cavity through the internal suction portion (23) in the upper region (22) of the bell-shaped cover (20), any one of claims 1 to 4 The device (1) described. The wall (15) and the bell-shaped cover (20) of the partitioned chamber (14) are made of plastic and at least heat the liquid additive (2) inside the tank (16). The apparatus (1) according to claim 5 , wherein at least one section of one heater (11) is at least partially embedded in the bell-shaped cover (20). A method for operating a device (1) for providing a liquid additive (2) according to any one of claims 1 to 6 , comprising at least the following steps:
a) delivering the liquid additive (2) from the tank (4) to the additive distributor (5) in the delivery direction (8) along the delivery path (3);
b) stopping the transmission;
c) at least partially draining the section (6) of the delivery path (3); and d) providing insulation (9) to the jacket (7) by the drained delivery path (3). A method of operating a device for providing a liquid additive, comprising the step of forming. The liquid additive (2) is fed back from the delivery path (3) to the tank (4) in the opposite direction to the delivery direction (8), thereby causing the section (6) of the delivery path (3) to pass through. The method according to claim 7 , wherein the liquid is drained. Draining said section (6) of the delivery channel (3) by the liquid additive in said section (6) of the delivery channel (3) (2) is at least partially evaporated, claim 7 The method described. An internal combustion engine (25), an exhaust gas treatment apparatus for purifying exhaust gas of the internal combustion engine (25) and (26), according to claim 1, liquid additive (2) can be supplied to the exhaust gas treatment device (26) A motor vehicle (24), characterized in that it comprises a device (1) according to any one of claims 1 to 6 .

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